The present invention relates to a new flavoring material, cinnamic aldehyde propylene glycol acetal (hereinafter "CAPGA"), and its use as a flavor ingredient. This chemical is also called 2-styryl-4-methyl-l,3-dioxolane, or 2-styryl-5-methyl-1,3-dioxolane. More particularly, the present invention relates to the use of CAPGA to prolong and enhance the flavor of chewing gum and other consumable items.
Cinnamic aldehyde is often the primary ingredient in cinnamon flavoring. Cinnamic aldehyde also is used to enhance fruit and many other flavors. Cinnamic aldehyde has been added to a variety of foods, including gum. In chewing gum, however, the cinnamic aldehyde flavor dissipates after only a few minutes of chewing. Methods of flavor prolongation, including the chemical combination of cinnamic aldehyde with other moieties, have been investigated.
On page 315 of West et al. "Synthetic Perfumes: Their Chemistry and Preparation," published by Edward, Arnold & Co., London, England, 1949, cinnamaldehyde dimethyl acetal is reported to "have a fine cinnamon-cassia odor which renders it useful in some Chanel-like fancy perfume and in oriental types like Tabac Blond and Fleur de Tabac." Cinnamaldehyde diethyl acetal also is discussed.
Cinnamaldehyde dimethyl acetal and diethyl acetal also were mentioned in "Perfume and Flavor Chemicals (Aroma Chemicals)" by Arctander, privately published in Montclair, N.J. in 1969. The dimethyl acetal was described as practically colorless, carrying little or none of the odor with which the free aldehyde is associated. The diethyl acetal was described as having a "faint but fresh green slightly spicy oily sweet odor and a mild and oily sweet taste" (Id. at 620). In his definitive work "Perfume and Flavor Chemicals", Arctander judged the diethyl acetal to be of little value in flavoring because like most other acetals, the diethyl acetal was unstable under mildly acid conditions.
Arctander also reported on cinnamaldehyde-2,4-dihydroxy-4-methyl-pentane acetal, describing it as having a "soft, tenacious, natural, cinnamon-type odor, not nearly as harsh as cinnamic aldehyde itself" (Id. at 621).
Arctander also reported on cinnamaldehyde ethylene glycol acetal, describing it as having a "sweet-spicy cinnamon-allspice taste, but not quite as sweet as the aldehyde" (Id. at 623). Arctander indicated that this latter acetal would be useful in flavor compositions, including all-spice, cassia, cinnamon, clove and various spice blends.
These cinnamaldehyde acetals were recognized as relatively unstable, especially in aqueous media, and thus were considered undesirable as perfume or flavor ingredients.
Acetals have been combined with other flavor chemicals to produce longer-lived chemicals. U.S. Pat. No. 3,898,283 (Schreiber et al.) teaches methods to produce phenyl pentenals, as well as their acetals.
U.S. Pat. No. 3,908,023 (Schreiber et al.) further teaches the production of cinnamon-like flavors with phenyl pentenals and their acetals. However, Schreiber points out that these chemicals are very stable, only hydrolyzing under "intense hydrolytic conditions." These conditions include a pH which is either under 2.5 or greater than 11.5, far different from the neutral pH of saliva. This reference teaches that 1,2- and 1,3-propylene glycol may be used in acetals to stabilize phenyl pentenals (col. 6, line 13).
U.S. Pat. No. 3,879,425 (Hall et al.) teaches that 3-phenyl,-4-pentenal ethylene acetal is a stable precursor for the aldehyde, which has a green floral fragrance. It teaches that a variety of phenyl pentenals, can be combined with a variety of acetals. A list of such acetals includes propylene glycol acetal (col. 9, lines 50-51).
U.S. Pat. No. 4,571,344 (Pittet et al.) teaches preparation of a sustained release flavor by combining dithioethers of phenyl alkenals with silica and propylene glycol (cols. 23 and 24). Pittet also teaches using the silica mixture in chewing gum (col. 24, lines 43-54). Pittet also reports long-lasting flavor with the dithioether flavor alone (col. 24, lines 58-64).